choke valves are supplied in two types: Positive and Adjustable. Designed as per API6A,API 16C,NACE MR0175 . choke valve wellhead China Structure type needle, barrel, cage,orifice and wedge Working pressure 3000psi,5000psi, 10000psi, 15000psi  Nominal bore: 2 1/16",2 9/16",3 1/16" 3 1/8,4 1/16 POSITIVE CHOKE Positive chokes allow external adjustment in orifice size 5/64" through 48/64" in 1/64" increments AQE wellhead valves ADJUSTABLE CHOKE Adjustable chokes Indicator sleeve reveals orifice size in 1/64"increments needed for conversion to an equivalent positive choke size